To maintain infrastructure such as structures, inspections are made and when problems are found, the problematic portions are repaired. When such work is performed, labor and expenses are not sufficient in many cases. To solve the problem, some methods employ Information and Communication Technology (ICT).
Such solutions that use ICT include techniques for capturing images of structures with image sensors, drones, robots, and the like to increase inspection efficiency and accuracy. For example, Japanese Laid-open Patent Publication No. 62-281582 discusses a technique for storing image data obtained by using a measuring vehicle or a sensor in a database and analyzing the image data stored in the database to detect a problem and estimate deterioration from aging for efficient structure inspection. In order to accurately detect a problem in a structure, it is preferable that high-resolution image data be used.
In this technique, to store image data in a database, a storage having an adequate storage capacity is to be provided, and thus the storage cost is increased. In order to store a large amount of data, for example, a technique discussed in Japanese Laid-Open Patent Publication No. 2005-136594 distributes and stores data in a plurality of devices.
In the above-described known techniques, however, image data compression is not effectively performed.
For example, in order to reduce merely the data capacity of image data, the image data may be compressed; however, compressing the image data may decrease the quality of the image data and the accuracy for detecting a problem in a structure.